How to Provide Documentation for a Disabled Family Member Exemption

I take care of my disabled mother. She lives on her own but needs transportation to all of her appointments and errands. I also pay for her groceries at least once a month, fuel costs, and some of her utilities. I understand I need to provide some receipts to prove this. I don’t really keep the receipts for groceries or fuel. I do have some of her utilities bills I have paid, but they don’t send receipts when you pay an electric bill for instance. What should I provide to make sure I can qualify for this exemption?